Combined motor and speed control device



Jan. 24, 1939.

.L JEPsoN COMBINED MOTOR AND SPEED coNTEoL DEVICE Filed sept. 3, l1913s 2 Sheets-Sheet l ww @TLM w w 5% Jan. 24, 1939. l. JEPsoN COMBINED MOTOR AND SPEED CONTROL DEVIOE Filed Sept. 5, '1936 2 Sheets-Sheet 2 Patented Jan. 24, 1939 PATENT OFFICE COMBINED MOTOR AND SPEED lCONTROL DEVICE Ivar Jepson, Chicago, Ill., aignor to Chicago Flexible Shaft Company, Chicago, Ill., a corporation of Illinois Appuemen september s, me. serai Ne. 99.134 1o omnia (cl. 11i-zzz) This invention relates to speed control mechanism for electric motors and is directed more particularly to pneumaticaily operated means for controlling and regulating the vmotor speed.

'Ihe invention contemplates a motor and a speed control mechanism therefor wherein a flow of air is generated by the motor and a contacting device is positioned in said ow to make and break the current in response to the ilow of air embodying improved structural characteristics in the air generating means and in the contact ac-` tuating elements. h

I have also aimed to provide improved assembly features whereby the cost of construction is materially reduced.

Another object of the invention is the provision of a pneumatically operated contacting device of uniform and sensitive operation.

Other objects and attendant advantages will be apparent from the following description and the accompanying drawings, in which,

Flgurel is a longitudinal section through a portable mixer unit showing the motor and speed control mechanism;

Fig. 2 is a section on the line 2-2 of Figure 1;

Fig. 3 is a section on the line 3-3 of Figure 1; Fig. 4 is a section on the line 4-4 of Figure 1; Fig. 5 is a section on the line 5-5 of Figure 1;

Fig. 6 is a section on the line 5--5 of Figure l;

Fig. '7 is a section similar to Fig. 2 showing a modied form, and

Fig. 8 is a perspective view of the vane shown l inFig.7.

The invention is herein shown embodied in a mixer unit of well known type having a motor 1, armature 8 carried on an armature shaft 3, the forward end of which is provided with a worm II for driving a pair of laterally spaced spindles indicated generally by the numeral I2 within which beater blades are adapted to be positioned to perform a mixing or beating operation. A casing I3 has spaced depending -ears I4 which serve to support the mixer unit upon a suitable pedestal for stationary use of the mixer. 'A handle I5, structurally disclosed in greater detail and claimed in another application, `serves for manual manipulation of the mixer unit.

The casing I3 is of such design as to constitute with end closure members I5 and I1 a complete enclosure for the motor, gear chamber, and speed control mechanism. The casing has upper and lower bosses ls and le within 'wnien the spindles I2Vare carried, and has a gear chamber designated tioned. The end closure member I5has a portion 22 which closes the forward end of the gear chamber 2| so as to retain lubricant therein.

a disk 23 is secured on its annulus on the inner wall of the casing I3 to the rear of the motor 1 and has a central opening 24 through which the armature shaft 8 passes. An impeller housing member designated generally by 25 is positioned rearwardly of the disk 23 and'has van impeller chamber 25 formed by an annular wall 21 which seats against the disk 23. The housing member has a boss 28 within which a sleeve bearing 28 is positioned for the reception of the rear end of the armature shaft 8, a cap 3l being carried on the boss and having a pressure plate 32 forming an end thrust bearing for the shaft. An impeller 33 is positioned on the armature shaft 8 within the chamber -25 and rotates with the shaft to draw air intothe chamber 25 through the opening 2l of the plate 23', the air being discharged through a plurality of openings 34 on the annulus of the impeller housing member 25 as best shown in Figs. 3 and 6.

A mounting bracket designated generally by the numeral 35 is positioned to the rear oi the impeller housing 25 and is spaced therefrom by annularly arranged spacing parts 31 and 33 on the housing and the bracket, the part 31 being an annular wall on the bracket, the bracket being attached to the housing by means of annularly arranged screws 38. The wail 31 serves as a reenforcement for the face of the bracket and also functions with the part 38 to form a chamber III into which the air is conducted and which serves to equalize small variations in the rate of air delivery from the impeller. Attached to the forward side of the bracket 35 is an arcuate linsulation member 4I upon which a resistor is carried, which resistor shunts the contact points presently to be described. A condenser I2 is carried on the bracket and interposed between the bracket and the impeller housing, the housing member having seats 53 in which the condenser rests. The resistor, condenser and the bearing boss 28 and associated parts are arranged so as to interfit in the chamber in such manner as to produce a compact, economical and eiiicient structure. The bracket 35 is in this instance and preferably formed of insulation material and is 'conveniently molded of synthetic resin such as Bakelite or Micarta." An opening u is formed in the bracket 35, which Ainthis instance is relatively large and of rectangular shape. This opening is surrounded on three sides by a rib 45 to provide inner walls for the opening o'f bracket..

Attached to the bracketand extending laterally across the opening 44 is a vane 46, iny this instance rectangular inshape and of vslightly smaller width than the internal width of the opening 44 and of sulcient length to permit 1 attachment by means of rivets'or other fastening members 41 along one end, the opposite end being spacd slightly from the end of the open- Aing adjacent thereto. The vane is in this instance formed of a resilient metal so as to be capable of distortion about `its supporting end. The vane carries a contact 46 and has an opening 49 for a purpose presently to be described. It will be observed that the vopening 44 and the vane 46 need not necessarily be 'rectangular' but may take any of a wide variety jof shapes and yet satisfactorily perform the functions which will appear from this description.l A manually adjustablecontact 5 I is carried on a Y-shaped contact carrier 52 having arms 63 and 54 attached to the bracket by means of screws or other fastening members 55 and 56. The arm 53 is electrically connected to one end .of the resistor 4I` through a conductor 51 whereas the opposite end of the resistor is connected to the vane 46 through a conductor 56. The position .of the contact carrier 52 and the contact 5I is adjustable through a manually adjusted pin 66 having an insulating button 6I thereon bearing against'the carrier at the junction of the arms 53 and 54, abutment 6l passingthrough the opening 49 of the vane 46.

The pin 69 is threaded into a split sleeve 62 (Fig. 2) seated for reciprocation in a boss/63 of the cap I-1, which reciprocation is manually brought about through rotationy of afknob 64 rotatably carried on a boss 65 on the cap I1, the knob having a groove 66 of variable depth for the purpose of moving the sleeve 62 and associated parts inward and outward upon rotation of the knob.v

A contact 61 (Figure 1) is carried on the bracket 66 and 4cooperates with a contact 6 6 carried on a spring contact member 69 to form a switch. This switch is actuated by a Pili 1| seated for longitudinal movement in the cap I1 and arranged at one position of the knob 6 4 to drop into an' opening 12 vtherein to permit the Opening oi' the contacts 61 and 66. A projection 16 on the knob 64 is received in a groove 14 in the cap I1, the grooves extending through a limited arc so that the ends thereof serve as l stops for the rotation of the knob to limit the.'

degree of movement thereof. The cap I1 has a comprises a centrifugal memberdesignated generally by the numeral 11 Ahaving weight members 16 and 16 adapted at low speeds of the motor to urge a friction disk 6I carried on the' armature shaft 6 into surface contact with a ange 62 on the bearing member 6 6'positioned in the wall ofv the gear chamber 2I. This arrangement is such thatthe maximumbrakin'g action occurs at 'the the vane.

sembly or distortion of the fective to cool the motor andto cool the resistor element.

4lower speed and as the speed of the motor increases the braking action progressively decreases.

the -brake being entirely released at a moderate motor speed.

Figure 1 shows the parts in the o position with the contact points 61 and 66 open.A When the knob 64 is rotated slightly these contact points are closed, causing the motor to start and to rotate at its lowest speed. Thereupon air is drawn into` the front of the casing I6 through openings in the cap I6 by action of the impeller 36 and is moved by the impeller through the openings 64 of' the impeller housing member.

The air then passes over the resistor 4I, through the opening 44 of the bracket, and out through the slots 15 of the cap I1. Upon passing through the opening 44, the now or stream of air is impeded by the vane 46, the air causing the vane to be moved outwardly in the openingor tunnel 44, thereby moving the contact point 46. When the iiow of air exerts a predetermined force on the vane 46 the contact points 46 and 6I will be opened so that the current supply to the motor will be through the resistor 4I. Likewise. when the speed of the motor decreases to a point at which the force exerted on the vane 46 is insuflicient to maintain the' contact points 46 and 5I open, these points will be closed and current will again ilow directly to the motor. By rotation oi the knob 64 the contact point 6I may be adjusted in position so that more force is required to cause the opening of the contacts 46 and 6I;` in other words, so that theY vane 46 will have to be moved a' greater distance against the inthe vane in order to open .tion that a vane of the type shown inbFig. 6

is employed and a button is threaded into the bore of the boss and projects forwardly into the casing to cooperate with the vane. 'I'he vane, indicated generally by the numeral 64, diiers from the vane 46 in that it is slotted along its attached end and a short distance alongthe sides. as indicated at 65,l and has a V-shaped spring member 66 attached by one leg 61 to the rearward face, the opposite leg 66 having a depression as shown at 66 against which a button of insulation material 6I bears to apply spring tension t0 'Through this means the tension on the vane is imparted from the casing rather than ,from the bracket 36 so that slight changes inthe position -of this bracket, such as might be occasionedby hard usage, minor differences in asbracket will not aiect y the'speed setting. I n

Attention is directed to the fact that thev air emerging from the openings 64 in theA impeller housing. member passes directly over the resistor so that this forced draft keeps the resistor at a relatively low temperature. The air used in the' control of the motor speed is. therefore, abo eL,

Attention is also directed tothe met mathe'- cause of theribs 46 the openingfhas a depth in the direction oi the vane movement. such as to maintain approximately the same air opening throughout the length oi' the vane stroke, whereby maximum movement is obtained. Further more, the opening 44 is slightly larger than the vane so as to allow free movement ot the vane withoutj friction and also to allow air to pall' 7l A feature of the invention lies in the manner in which the various elements are coordinated within the casing, the impeller being positoned adjacent the amature whereby the end of the amature may be carried in a relatively long and fixed bearing on the impeller housing, the bracket 35 being positioned directly adjacent the impeller housing in such manner ,as to provide an air chamber which acts to equalize small variations in the pressure and wherein the condenser, the resistor, and the bearing for the rear of the armature shaft are nested. Also the provision of an annular wall on the bracket member which serves to reenforce the same and within the concave side of which various parts of the governor` assembly are adapted to be carried.

The device described is of particular merit because of its extreme sensitiveness and because of the great uniformity of operation whereby a nicety of control is obtained over the speed of the motor such as has heretofore been unobtainable.

I am aware that numerous alterations and `changes may be made in the structure as herein described and shown and I do not wish to be limited except as required by the prior art and the scope of the appended claims, in which, I claim:

l. The combination in an electric motor, of a casing having parallelly disposed transverse partitions forming' an intercommunicating motorV chamber, an impeller chamber adjacentthereto, and an air reservoir, said reservoir having an outlet, a motor in the motorchamber, contacts relatively movable to open vand close the circuit through said motor, means in said impeller chamber to draw air from said motor chamber and deliver the same to said reservoir in proportion to the speed of the motor, and means comprising a flexible sheet metal vane fixed in said outlet positioned to be fiexed by the force of air moving therethrough to open and close the contacts in response to said force whereby to maintain a predetermined motor speed.

2. The lcombination in an electric motor, of a casing having parallelly disposed transverse partitions forming a motor chamber, an'impeller chamber adjacent thereto, and an air reservoir, said reservoir having an outlet, the partition between said impeller chamber and said air reser- Voir having a plurality of annularly spaced openings for the delivery of air to said reservoir and the partition between said motor chamber and said impeller chamber having a'centrally disposed opening for the passage of air from the motor chamber to the impeller chamber, a motor in the motor chamber, contacts relatively movable to open and close .the circuit through said motor, means in said impeller chamber to draw air from said motor chamber anddeliver the same to said reservoir in proportion to the speed of the motor,

and means in saidl outlet positioned to be actuated by the force of air moving therethrough to open and cl'ose the contacts in response to saidk force whereby to maintain a predetermined motor speed.

3. The combination in a speed regulator vfor electric motors, oi' contacts arranged for relative movement to make and break the circuit through a motor, means driven by the motorfor develovins a ow of air proportional to the speed of the motor, and a vane for moving said contacts positioned in the flow of air comprising a spring member rigidly secured along one edge, the opthe 'said chamber, and

bythe motor for developing ailow of air pro--v Aportlonal 'to the speed of the motor. of an air tunnel through which the air is caused to flow.' Va vane comprising a spring member rigidly secured along one edge, the opposed edge thereof being free to move under the influence of the in a speed regulator forv.

air now, for moving said contacts positioned in thel tunnel transversely thereof-to maintain a predetermined motor speed, a motor casing enclosing said speed regulator, and spring means acting between the casing and said vane for ap piying a spring tension thereto.

5. The combination in a speed regulator forv electric motors, of the type having a pair of contacts arranged for relative movement to make and break the circuit through a motor, and means drivenby the motor for developing a flow of proportional to the speed of themotor, of an air tunnel through which the air is caused to flow, a' vane for supporting one of said contacts for movement' to make and break said circuit comprising a sheet vof resilient metal attached at one edge transversely in said tunnel, the sheet having a slot adjacent said fastened edge to permit the remainder of the sheet to hinge thereon, and spring means acting between the remainder of the sheet and a stationary element'to apply spring pressure thereto tending to make said contacts.

6. The combination in a motor and speed regulator therefor of -a casing, a motor positioned therein, spaced from one end and having an armature, a plate annularly secured in said end and the passage of air, an impeller housing comprising a plate having an annular wall seated in said casing and against said first mentioned plate to space the impeller plate therefrom and form an impeller chamber, said housing also having a centrally disposed bearing for supporting the end of the armature shaft within the casing and spaced from the end thereof, an impeller on the armature shaft between saidl plates for generating a flow. of air, and contact means in said end of the casing for controlling the speed of the motor in response to the ilow of air from said housing.

'1. The combination in a motor and speed regulator therefor of a casing, a motor positioned therein spaced from one end and having an armature and shaft, an air impeller on said shaft, a plate positioned transversely in said casing and seating annularly therein, the plate having.a centrally disposed bearing member extending rearwardly on the plate and providing lateral and end thrust support for the armature shaft, a bracket comprising a transverse plate of insulatio materialseated annularly in said casing in rearward spaced relation to the first mentioned plate, an annular wall on the last mentioned plate extending forwardly for reenforcing the same and spacing said plates to form anlair 'chamber to receive air from said impeller, and. an arcuate resistor carried on the forward side oi' the last mentioned plate, said plates being so spaced that the bearing and the resistor nest into contact means carried on the last mentioned plate for controlling the speed of the motor in response to the iiow of air from' 'said chamber.

8. The combination in a speed control mechanism for electric motors, of means driven by thek motor for developing a iiow oi air proportional to the speed of the motor, means to coniihe .the

iiow of air having an outlet provided with side walls to form a tunnel, a vane positioned in said tunnel transversely to the iiow'of air and movable through' a defined stroke under the. in-

iiuence vof the air, a movable contact point posi--l tionedon said vane, a resilient contact carrier positioned transversely of said tunnel and beyond the stroke of said vane, a normally st ationary contact positioned thereon to cooperate with the movable contact, and means operative on said contact carrier for manually moving the position of the stationary contact whereby to predetermine the speed of the 'motor at which said contacts will open and close.

9. 'Ihe combination in a speed control mechanism for electric motors, oi' -means driven by the motor for developing a flow of air proportional to the speed oi the motor, means to connue the iiow Voi' air having an outlet provided withl side walls to form a tunnel, a vane positioned in said tunnel transversely to theiiow of air and movable through a dened stroke under the` iniiuence of the air, a movable contact point positioned on said vane, a VI-shaped contact carrier positioned transversely oi*` said-tunnel and iixedly secured at the tree ends of its arms, a contact point positioned thereon adjacent the junction of said arms and arranged to cooperate rwith said movable contact to open and close the circuit through the motor and thereby maintain' a predetermined a slot adjacent said fastening edge to permit the y l remainder of the sheet to hinge thereabout, and

spring means attachedto the sheet intermediate its ends adapted to act between the sheet and a stationary element to apply spring pressure thereto.

IVAR JEPSON. 

